I have searched and searched for the answer to this problem on my own but now I need your help.

I have a Speedhut speedometer that I am trying to get to work correctly with my transplanted 5.3/6L80e combo using the E38 ECM speed output. I have tried all the combinations of options in the Speed tab of HP Tuners but only one (Speed Output Type: VehSerial; Vehicle Speed Output: Serial) will read the signal out of the ECM. However, the speedo reacts really strangely. First, on acceleration the speedo lags the actual speed badly. Then, on deceleration the reaction to the actual speed lags even more. Lastly, when coming to a stop the needle will stall at about 20pmh and then drop abruptly to zero after I have already been stopped for several seconds. Does anyone have any clue what could cause this?

Things I have tried:
All combinations of Speed Output Type and Vehicle Speed Output
Pull-up resistor on speedo wire from ECM (had no effect)
Metered the ECM wire and get a 12v signal on idle and about 6 volts when moving which seems correct since this a wave from 0-12V
Contact Speedhut Tech Support (they want me to wire directly to VSS which is not possible (i think) on 6L80e)

Any help is appreciated.

 

No one, nothing? I am going to have to rip my dash apart to send this back to Speedhut which I would very very much not like to do. If you have any thoughts, please share.

 

Did you program the speedhut speedo? You have to do that so it knows the ppm ...


T,

 

Yep...about 20 times exactly how they instruct. Still get the same behavior.

 

You're using a recalibrated ABS output, expect some issues

You can skip all that and use a GPS module. IIRC, Speedhut makes one too

 

Why do others not seem to have any issues using the same output? I really prefer not to buy another gps speedo at +$200. In retrospect I should have in the beginning. I guess I will just send it back for testing at least. The speedo reacts the same when connected directly to the VSS in the transfer case.

 

I thought speed hut had some canbus gauges for these swaps. I know dakota digital does and ive used them on these same swaps. Did the swap over 2yrs ago and no issues since and speedo works perfect.

Without the canbus gauge setup its alomost impossible to get tach and speedo output with tht setup.

 

The feed out of the e38 is bogus. Use the VSS directly off the trans, you can splice into it and leave it hooked to the E38 as well this will not harm anything as the VSS is passive. I had to do this to get my speedo working as well

 

Thanks guys. I don't want to buy any other equipment if necessary since the speedo was supposed to work with "all" vehicles. I was concerned to tap the VSS from the trans before the ECM as I heard it could draw too much current and start messing with the shift operations. Glad to know that isn't the case. I will look into that to see if there is a dedicated VSS feed in the 6L80e bundle to the ECM. I thought it was CAN bus.

 

CAN Bus is bogus. I have no idea what kind of trickery GM pulled with these genIV systems but SO FAR at least no tuning support exists to modify nearly enough of what we swappers need to use. Sure we can tune AF and timing, but transmission control is really only solid for factory equipped set ups. Soon as you start swapping engines and transmissions around? Your up the creek without a paddle because the OS is locked, the OS is also locked to specific BCM and TCM configs so genIV swaps overall are a major pita and I wont do another unless I require the 58x for extreme RPM. I'd recommend to anyone wanting genIV hardware to swap to a 24x reluctor and stick with the LS1 style PCM controller or go for a Holley system. I have no idea if Holley has decent control over the newer 6spd autos and higher.

Anyways I have the VSS spliced in ( bi-wired iirc is the proper term ) so the trans VSS out feeds the speedo, and the ECM although the ECM in my case has all sorts of VSS related issues so as of now I have no rev limiter, or I am stuck with 50% throttle. Arghhh ugly memories sorting all this out. Hope some of this helps your build

 

CAN Bus is the present and future of modern electronics. And the hobbyist is TOTALLY out of the scope of automotive engineers. We have to live with what is put out in the cars sold today, as it always has been. If you think they are gong to cater to the hobbyist you have a very narrow scope of the automotive world.

 

Where there is demand, there is market to be won EASY. If you think GM would currently be NEARLY as successful as they are without all us LS guys literally swapping every other brand in existence? You are sorely mistaken. While I agree 100% that automotive engineers are by and large out of touch with aftermarket performance enthusiasts consider the BBC woudlnt even exist IF an aftermarket automotive enthusiast did not have the know how to make an engine tick. The 409 was what GM offered prior to the first mystery motors and consider the sbc, the BBC, and then the LS1 and what WE the aftermarket hobbyists did with them.

Ignore us at your peril

Someone else will cater if the GM boys dont. Cest la vies

What we need is a Moates type dude to sort out the GEN IV and GEN V swap potential. HUGE market there for anyone clever as such

Narrow scope? Maybe, but its a big market in that scope.

 

The volume of LS engines swapped into ANYTHING is a drop in the bucket compared to the total volume of whole goods (cars and trucks) and service parts GM sells. OUR volume helps, yes, but don't delude yourself in grandeur thinking that we hobbyists carry GM's success on our shoulders.

 

Economics rule #1. Keep your existing customer base happy. Sam Walton said its a thousand times easier to hold onto a customer you already have, then to drag one single new one through the door. His results, speak. GM has already put the gaff into a lot of us with fast rotting trucks and the ONLY thing keeping them going is price, and wicked drive trains. The C5R program that whipped butt in 24hr Lemans which was a SPIN OFF of an aftermarket LS performance outfit and created MAJOR GLOBAL GM brand power, and appeal. No denying this

Anyways off topic, off point, we need better tuning solutions for CAN BUS systems so we can swap as need be. Theres a big market, a big demand and if left ignored will be a big loss imo

 

I guess the main point for this thread is- CANBus is here to stay. Adapt, embrace, and utilize...

 

Just to close the loop...

I tore the dash apart and sent it back to Speedhut for testing. It was programmed incorrectly. The fixed it and are sending it back. You would think they would test them prior to initial shipment. Oh well...

 

Glad you got a fix Scott. As for canbus (whatever the hell that means) and automatic transmissions - I installed all my old analog senders/switches, stuck with my VDO analog gauges and use a manual transmission (or as my Atlanta-based daughter calls it - theft deterrent) the way God intended.

The vast majority of GM engine swaps since the small block came out in 1955 have been with used engines -- engines GM already sold in a vehicle. Their crate engine sales volume is almost nothing compared to engine volume for use in new vehicles. They only sell them new/standalone because they're making them anyway. They couldn't care less about the hot rod/modding community - oh, they have a mouthpiece that says they care. But what they really care about right now is 1) electric possibilities and 2) vehicle sales in China. As for 'successful' - GM's a big *** dinosaur that is taking FOREVER to die. They've been unable to compete in the car market with cars produced just about any place else in the world - especially Japan and Korea - since the early 70's. Ford just announced they're about to stop producing cars at all - just focusing on trucks and SUV's and the Mustang. GM is practically already there - they have not built a competitive small or mid-size sedan in almost 50 years. Trucks, SUV's and old people (yeah, I'm one) keep them afloat. Even Corvette sales will suffer (Mustang, Camaro too) as the baby boomers die off. Ironically - sales in the U.S. are not even the highest priority for GM right now. If they don't succeed in China....they won't continue to exist as we've known them. Toyota and VW will, as they have already, roll on by...

Damn, I got sucked in again!